// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef INCLUDED_FROM_MACRO_ASSEMBLER_H
#error This header must be included via macro-assembler.h
#endif

#ifndef V8_X64_MACRO_ASSEMBLER_X64_H_
#define V8_X64_MACRO_ASSEMBLER_X64_H_

#include "src/bailout-reason.h"
#include "src/base/flags.h"
#include "src/contexts.h"
#include "src/globals.h"
#include "src/x64/assembler-x64.h"

namespace v8 {
namespace internal {

    // Convenience for platform-independent signatures.
    typedef Operand MemOperand;

    class StringConstantBase;

    enum RememberedSetAction { EMIT_REMEMBERED_SET,
        OMIT_REMEMBERED_SET };
    enum SmiCheck { INLINE_SMI_CHECK,
        OMIT_SMI_CHECK };

    struct SmiIndex {
        SmiIndex(Register index_register, ScaleFactor scale)
            : reg(index_register)
            , scale(scale)
        {
        }
        Register reg;
        ScaleFactor scale;
    };

    enum StackArgumentsAccessorReceiverMode {
        ARGUMENTS_CONTAIN_RECEIVER,
        ARGUMENTS_DONT_CONTAIN_RECEIVER
    };

    class StackArgumentsAccessor {
    public:
        StackArgumentsAccessor(Register base_reg, int argument_count_immediate,
            StackArgumentsAccessorReceiverMode receiver_mode = ARGUMENTS_CONTAIN_RECEIVER,
            int extra_displacement_to_last_argument = 0)
            : base_reg_(base_reg)
            , argument_count_reg_(no_reg)
            , argument_count_immediate_(argument_count_immediate)
            , receiver_mode_(receiver_mode)
            , extra_displacement_to_last_argument_(
                  extra_displacement_to_last_argument)
        {
        }

        StackArgumentsAccessor(Register base_reg, Register argument_count_reg,
            StackArgumentsAccessorReceiverMode receiver_mode = ARGUMENTS_CONTAIN_RECEIVER,
            int extra_displacement_to_last_argument = 0)
            : base_reg_(base_reg)
            , argument_count_reg_(argument_count_reg)
            , argument_count_immediate_(0)
            , receiver_mode_(receiver_mode)
            , extra_displacement_to_last_argument_(
                  extra_displacement_to_last_argument)
        {
        }

        StackArgumentsAccessor(Register base_reg,
            const ParameterCount& parameter_count,
            StackArgumentsAccessorReceiverMode receiver_mode = ARGUMENTS_CONTAIN_RECEIVER,
            int extra_displacement_to_last_argument = 0);

        Operand GetArgumentOperand(int index);
        Operand GetReceiverOperand()
        {
            DCHECK(receiver_mode_ == ARGUMENTS_CONTAIN_RECEIVER);
            return GetArgumentOperand(0);
        }

    private:
        const Register base_reg_;
        const Register argument_count_reg_;
        const int argument_count_immediate_;
        const StackArgumentsAccessorReceiverMode receiver_mode_;
        const int extra_displacement_to_last_argument_;

        DISALLOW_IMPLICIT_CONSTRUCTORS(StackArgumentsAccessor);
    };

    class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
    public:
        using TurboAssemblerBase::TurboAssemblerBase;

        template <typename Dst, typename... Args>
        struct AvxHelper {
            Assembler* assm;
            // Call an method where the AVX version expects the dst argument to be
            // duplicated.
            template <void (Assembler::*avx)(Dst, Dst, Args...),
                void (Assembler::*no_avx)(Dst, Args...)>
            void emit(Dst dst, Args... args)
            {
                if (CpuFeatures::IsSupported(AVX)) {
                    CpuFeatureScope scope(assm, AVX);
                    (assm->*avx)(dst, dst, args...);
                } else {
                    (assm->*no_avx)(dst, args...);
                }
            }

            // Call an method where the AVX version expects no duplicated dst argument.
            template <void (Assembler::*avx)(Dst, Args...),
                void (Assembler::*no_avx)(Dst, Args...)>
            void emit(Dst dst, Args... args)
            {
                if (CpuFeatures::IsSupported(AVX)) {
                    CpuFeatureScope scope(assm, AVX);
                    (assm->*avx)(dst, args...);
                } else {
                    (assm->*no_avx)(dst, args...);
                }
            }
        };

#define AVX_OP(macro_name, name)                                                 \
    template <typename Dst, typename... Args>                                    \
    void macro_name(Dst dst, Args... args)                                       \
    {                                                                            \
        AvxHelper<Dst, Args...> { this }                                         \
            .template emit<&Assembler::v##name, &Assembler::name>(dst, args...); \
    }

        AVX_OP(Subsd, subsd)
        AVX_OP(Divss, divss)
        AVX_OP(Divsd, divsd)
        AVX_OP(Xorps, xorps)
        AVX_OP(Xorpd, xorpd)
        AVX_OP(Movd, movd)
        AVX_OP(Movq, movq)
        AVX_OP(Movaps, movaps)
        AVX_OP(Movapd, movapd)
        AVX_OP(Movups, movups)
        AVX_OP(Movmskps, movmskps)
        AVX_OP(Movmskpd, movmskpd)
        AVX_OP(Movss, movss)
        AVX_OP(Movsd, movsd)
        AVX_OP(Pcmpeqd, pcmpeqd)
        AVX_OP(Pslld, pslld)
        AVX_OP(Psllq, psllq)
        AVX_OP(Psrld, psrld)
        AVX_OP(Psrlq, psrlq)
        AVX_OP(Addsd, addsd)
        AVX_OP(Mulsd, mulsd)
        AVX_OP(Andps, andps)
        AVX_OP(Andnps, andnps)
        AVX_OP(Andpd, andpd)
        AVX_OP(Orpd, orpd)
        AVX_OP(Cmpeqps, cmpeqps)
        AVX_OP(Cmpltps, cmpltps)
        AVX_OP(Cmpleps, cmpleps)
        AVX_OP(Cmpneqps, cmpneqps)
        AVX_OP(Cmpnltps, cmpnltps)
        AVX_OP(Cmpnleps, cmpnleps)
        AVX_OP(Cmpeqpd, cmpeqpd)
        AVX_OP(Cmpltpd, cmpltpd)
        AVX_OP(Cmplepd, cmplepd)
        AVX_OP(Cmpneqpd, cmpneqpd)
        AVX_OP(Cmpnltpd, cmpnltpd)
        AVX_OP(Cmpnlepd, cmpnlepd)
        AVX_OP(Roundss, roundss)
        AVX_OP(Roundsd, roundsd)
        AVX_OP(Sqrtss, sqrtss)
        AVX_OP(Sqrtsd, sqrtsd)
        AVX_OP(Ucomiss, ucomiss)
        AVX_OP(Ucomisd, ucomisd)

#undef AVX_OP

        void PushReturnAddressFrom(Register src)
        {
            pushq(src);
        }
        void PopReturnAddressTo(Register dst) { popq(dst); }

        void Ret();

        // Return and drop arguments from stack, where the number of arguments
        // may be bigger than 2^16 - 1.  Requires a scratch register.
        void Ret(int bytes_dropped, Register scratch);

        // Load a register with a long value as efficiently as possible.
        void Set(Register dst, int64_t x);
        void Set(Operand dst, intptr_t x);

        // Operations on roots in the root-array.
        void LoadRoot(Register destination, RootIndex index) override;
        void LoadRoot(Operand destination, RootIndex index)
        {
            LoadRoot(kScratchRegister, index);
            movq(destination, kScratchRegister);
        }

        void Push(Register src);
        void Push(Operand src);
        void Push(Immediate value);
        void Push(Smi smi);
        void Push(Handle<HeapObject> source);

        // Before calling a C-function from generated code, align arguments on stack.
        // After aligning the frame, arguments must be stored in rsp[0], rsp[8],
        // etc., not pushed. The argument count assumes all arguments are word sized.
        // The number of slots reserved for arguments depends on platform. On Windows
        // stack slots are reserved for the arguments passed in registers. On other
        // platforms stack slots are only reserved for the arguments actually passed
        // on the stack.
        void PrepareCallCFunction(int num_arguments);

        // Calls a C function and cleans up the space for arguments allocated
        // by PrepareCallCFunction. The called function is not allowed to trigger a
        // garbage collection, since that might move the code and invalidate the
        // return address (unless this is somehow accounted for by the called
        // function).
        void CallCFunction(ExternalReference function, int num_arguments);
        void CallCFunction(Register function, int num_arguments);

        // Calculate the number of stack slots to reserve for arguments when calling a
        // C function.
        int ArgumentStackSlotsForCFunctionCall(int num_arguments);

        void CheckPageFlag(Register object, Register scratch, int mask, Condition cc,
            Label* condition_met,
            Label::Distance condition_met_distance = Label::kFar);

        void Cvtss2sd(XMMRegister dst, XMMRegister src);
        void Cvtss2sd(XMMRegister dst, Operand src);
        void Cvtsd2ss(XMMRegister dst, XMMRegister src);
        void Cvtsd2ss(XMMRegister dst, Operand src);
        void Cvttsd2si(Register dst, XMMRegister src);
        void Cvttsd2si(Register dst, Operand src);
        void Cvttsd2siq(Register dst, XMMRegister src);
        void Cvttsd2siq(Register dst, Operand src);
        void Cvttss2si(Register dst, XMMRegister src);
        void Cvttss2si(Register dst, Operand src);
        void Cvttss2siq(Register dst, XMMRegister src);
        void Cvttss2siq(Register dst, Operand src);
        void Cvtqsi2ss(XMMRegister dst, Register src);
        void Cvtqsi2ss(XMMRegister dst, Operand src);
        void Cvtqsi2sd(XMMRegister dst, Register src);
        void Cvtqsi2sd(XMMRegister dst, Operand src);
        void Cvtlsi2ss(XMMRegister dst, Register src);
        void Cvtlsi2ss(XMMRegister dst, Operand src);
        void Cvtlui2ss(XMMRegister dst, Register src);
        void Cvtlui2ss(XMMRegister dst, Operand src);
        void Cvtlui2sd(XMMRegister dst, Register src);
        void Cvtlui2sd(XMMRegister dst, Operand src);
        void Cvtqui2ss(XMMRegister dst, Register src);
        void Cvtqui2ss(XMMRegister dst, Operand src);
        void Cvtqui2sd(XMMRegister dst, Register src);
        void Cvtqui2sd(XMMRegister dst, Operand src);
        void Cvttsd2uiq(Register dst, Operand src, Label* fail = nullptr);
        void Cvttsd2uiq(Register dst, XMMRegister src, Label* fail = nullptr);
        void Cvttss2uiq(Register dst, Operand src, Label* fail = nullptr);
        void Cvttss2uiq(Register dst, XMMRegister src, Label* fail = nullptr);

        // cvtsi2sd instruction only writes to the low 64-bit of dst register, which
        // hinders register renaming and makes dependence chains longer. So we use
        // xorpd to clear the dst register before cvtsi2sd to solve this issue.
        void Cvtlsi2sd(XMMRegister dst, Register src);
        void Cvtlsi2sd(XMMRegister dst, Operand src);

        void Lzcntq(Register dst, Register src);
        void Lzcntq(Register dst, Operand src);
        void Lzcntl(Register dst, Register src);
        void Lzcntl(Register dst, Operand src);
        void Tzcntq(Register dst, Register src);
        void Tzcntq(Register dst, Operand src);
        void Tzcntl(Register dst, Register src);
        void Tzcntl(Register dst, Operand src);
        void Popcntl(Register dst, Register src);
        void Popcntl(Register dst, Operand src);
        void Popcntq(Register dst, Register src);
        void Popcntq(Register dst, Operand src);

        // Is the value a tagged smi.
        Condition CheckSmi(Register src);
        Condition CheckSmi(Operand src);

        // Jump to label if the value is a tagged smi.
        void JumpIfSmi(Register src, Label* on_smi,
            Label::Distance near_jump = Label::kFar);

        void JumpIfEqual(Register a, int32_t b, Label* dest)
        {
            cmpl(a, Immediate(b));
            j(equal, dest);
        }

        void JumpIfLessThan(Register a, int32_t b, Label* dest)
        {
            cmpl(a, Immediate(b));
            j(less, dest);
        }

        void Move(Register dst, Smi source);

        void Move(Operand dst, Smi source)
        {
            Register constant = GetSmiConstant(source);
            movq(dst, constant);
        }

        void Move(Register dst, ExternalReference ext);

        void Move(XMMRegister dst, uint32_t src);
        void Move(XMMRegister dst, uint64_t src);
        void Move(XMMRegister dst, float src) { Move(dst, bit_cast<uint32_t>(src)); }
        void Move(XMMRegister dst, double src) { Move(dst, bit_cast<uint64_t>(src)); }

        // Move if the registers are not identical.
        void Move(Register target, Register source);

        void Move(Register dst, Handle<HeapObject> source,
            RelocInfo::Mode rmode = RelocInfo::EMBEDDED_OBJECT);
        void Move(Operand dst, Handle<HeapObject> source,
            RelocInfo::Mode rmode = RelocInfo::EMBEDDED_OBJECT);

        // Loads a pointer into a register with a relocation mode.
        void Move(Register dst, Address ptr, RelocInfo::Mode rmode)
        {
            // This method must not be used with heap object references. The stored
            // address is not GC safe. Use the handle version instead.
            DCHECK(rmode > RelocInfo::LAST_GCED_ENUM);
            movq(dst, Immediate64(ptr, rmode));
        }

        // Move src0 to dst0 and src1 to dst1, handling possible overlaps.
        void MovePair(Register dst0, Register src0, Register dst1, Register src1);

        void MoveStringConstant(Register result, const StringConstantBase* string,
            RelocInfo::Mode rmode = RelocInfo::EMBEDDED_OBJECT);

        // Convert smi to word-size sign-extended value.
        void SmiUntag(Register dst, Register src);
        void SmiUntag(Register dst, Operand src);

        // Loads the address of the external reference into the destination
        // register.
        void LoadAddress(Register destination, ExternalReference source);

        void LoadFromConstantsTable(Register destination,
            int constant_index) override;
        void LoadRootRegisterOffset(Register destination, intptr_t offset) override;
        void LoadRootRelative(Register destination, int32_t offset) override;

        // Operand pointing to an external reference.
        // May emit code to set up the scratch register. The operand is
        // only guaranteed to be correct as long as the scratch register
        // isn't changed.
        // If the operand is used more than once, use a scratch register
        // that is guaranteed not to be clobbered.
        Operand ExternalReferenceAsOperand(ExternalReference reference,
            Register scratch = kScratchRegister);

        void Call(Register reg) { call(reg); }
        void Call(Operand op);
        void Call(Handle<Code> code_object, RelocInfo::Mode rmode);
        void Call(Address destination, RelocInfo::Mode rmode);
        void Call(ExternalReference ext);
        void Call(Label* target) { call(target); }

        void CallBuiltinPointer(Register builtin_pointer) override;

        void LoadCodeObjectEntry(Register destination, Register code_object) override;
        void CallCodeObject(Register code_object) override;
        void JumpCodeObject(Register code_object) override;

        void RetpolineCall(Register reg);
        void RetpolineCall(Address destination, RelocInfo::Mode rmode);

        void Jump(Address destination, RelocInfo::Mode rmode);
        void Jump(ExternalReference ext);
        void Jump(Operand op);
        void Jump(Handle<Code> code_object, RelocInfo::Mode rmode,
            Condition cc = always);

        void RetpolineJump(Register reg);

        void CallForDeoptimization(Address target, int deopt_id);

        // Non-SSE2 instructions.
        void Pextrd(Register dst, XMMRegister src, int8_t imm8);
        void Pinsrd(XMMRegister dst, Register src, int8_t imm8);
        void Pinsrd(XMMRegister dst, Operand src, int8_t imm8);

        void CompareRoot(Register with, RootIndex index);
        void CompareRoot(Operand with, RootIndex index);

        // Generates function and stub prologue code.
        void StubPrologue(StackFrame::Type type);
        void Prologue();

        // Calls Abort(msg) if the condition cc is not satisfied.
        // Use --debug_code to enable.
        void Assert(Condition cc, AbortReason reason);

        // Like Assert(), but without condition.
        // Use --debug_code to enable.
        void AssertUnreachable(AbortReason reason);

        // Abort execution if a 64 bit register containing a 32 bit payload does not
        // have zeros in the top 32 bits, enabled via --debug-code.
        void AssertZeroExtended(Register reg);

        // Like Assert(), but always enabled.
        void Check(Condition cc, AbortReason reason);

        // Print a message to stdout and abort execution.
        void Abort(AbortReason msg);

        // Check that the stack is aligned.
        void CheckStackAlignment();

        // Activation support.
        void EnterFrame(StackFrame::Type type);
        void EnterFrame(StackFrame::Type type, bool load_constant_pool_pointer_reg)
        {
            // Out-of-line constant pool not implemented on x64.
            UNREACHABLE();
        }
        void LeaveFrame(StackFrame::Type type);

        // Removes current frame and its arguments from the stack preserving the
        // arguments and a return address pushed to the stack for the next call.  Both
        // |callee_args_count| and |caller_args_count_reg| do not include receiver.
        // |callee_args_count| is not modified, |caller_args_count_reg| is trashed.
        void PrepareForTailCall(const ParameterCount& callee_args_count,
            Register caller_args_count_reg, Register scratch0,
            Register scratch1);

        // Call a runtime routine. This expects {centry} to contain a fitting CEntry
        // builtin for the target runtime function and uses an indirect call.
        void CallRuntimeWithCEntry(Runtime::FunctionId fid, Register centry);

        void InitializeRootRegister()
        {
            ExternalReference isolate_root = ExternalReference::isolate_root(isolate());
            Move(kRootRegister, isolate_root);
        }

        void SaveRegisters(RegList registers);
        void RestoreRegisters(RegList registers);

        void CallRecordWriteStub(Register object, Register address,
            RememberedSetAction remembered_set_action,
            SaveFPRegsMode fp_mode);
        void CallRecordWriteStub(Register object, Register address,
            RememberedSetAction remembered_set_action,
            SaveFPRegsMode fp_mode, Address wasm_target);
        void CallEphemeronKeyBarrier(Register object, Register address,
            SaveFPRegsMode fp_mode);

        void MoveNumber(Register dst, double value);
        void MoveNonSmi(Register dst, double value);

        // Calculate how much stack space (in bytes) are required to store caller
        // registers excluding those specified in the arguments.
        int RequiredStackSizeForCallerSaved(SaveFPRegsMode fp_mode,
            Register exclusion1 = no_reg,
            Register exclusion2 = no_reg,
            Register exclusion3 = no_reg) const;

        // PushCallerSaved and PopCallerSaved do not arrange the registers in any
        // particular order so they are not useful for calls that can cause a GC.
        // The caller can exclude up to 3 registers that do not need to be saved and
        // restored.

        // Push caller saved registers on the stack, and return the number of bytes
        // stack pointer is adjusted.
        int PushCallerSaved(SaveFPRegsMode fp_mode, Register exclusion1 = no_reg,
            Register exclusion2 = no_reg,
            Register exclusion3 = no_reg);
        // Restore caller saved registers from the stack, and return the number of
        // bytes stack pointer is adjusted.
        int PopCallerSaved(SaveFPRegsMode fp_mode, Register exclusion1 = no_reg,
            Register exclusion2 = no_reg,
            Register exclusion3 = no_reg);

        // Compute the start of the generated instruction stream from the current PC.
        // This is an alternative to embedding the {CodeObject} handle as a reference.
        void ComputeCodeStartAddress(Register dst);

        void ResetSpeculationPoisonRegister();

        // ---------------------------------------------------------------------------
        // Pointer compression support

        // Loads a field containing a HeapObject and decompresses it if pointer
        // compression is enabled.
        void LoadTaggedPointerField(Register destination, Operand field_operand);

        // Loads a field containing any tagged value and decompresses it if necessary.
        // When pointer compression is enabled, uses |scratch| to decompress the
        // value.
        void LoadAnyTaggedField(Register destination, Operand field_operand,
            Register scratch = kScratchRegister);

        // Loads a field containing a HeapObject, decompresses it if necessary and
        // pushes full pointer to the stack. When pointer compression is enabled,
        // uses |scratch| to decompress the value.
        void PushTaggedPointerField(Operand field_operand, Register scratch);

        // Loads a field containing any tagged value, decompresses it if necessary and
        // pushes the full pointer to the stack. When pointer compression is enabled,
        // uses |scratch1| and |scratch2| to decompress the value.
        void PushTaggedAnyField(Operand field_operand, Register scratch1,
            Register scratch2);

        // Loads a field containing smi value and untags it.
        void SmiUntagField(Register dst, Operand src);

        // Compresses tagged value if necessary and stores it to given on-heap
        // location.
        void StoreTaggedField(Operand dst_field_operand, Immediate immediate);
        void StoreTaggedField(Operand dst_field_operand, Register value);

        // The following macros work even when pointer compression is not enabled.
        void DecompressTaggedSigned(Register destination, Operand field_operand);
        void DecompressTaggedPointer(Register destination, Operand field_operand);
        void DecompressAnyTagged(Register destination, Operand field_operand,
            Register scratch = kScratchRegister);

    protected:
        static const int kSmiShift = kSmiTagSize + kSmiShiftSize;
        int smi_count = 0;
        int heap_object_count = 0;

        // Returns a register holding the smi value. The register MUST NOT be
        // modified. It may be the "smi 1 constant" register.
        Register GetSmiConstant(Smi value);

        void CallRecordWriteStub(Register object, Register address,
            RememberedSetAction remembered_set_action,
            SaveFPRegsMode fp_mode, Handle<Code> code_target,
            Address wasm_target);
    };

    // MacroAssembler implements a collection of frequently used macros.
    class V8_EXPORT_PRIVATE MacroAssembler : public TurboAssembler {
    public:
        using TurboAssembler::TurboAssembler;

        // Loads and stores the value of an external reference.
        // Special case code for load and store to take advantage of
        // load_rax/store_rax if possible/necessary.
        // For other operations, just use:
        //   Operand operand = ExternalReferenceAsOperand(extref);
        //   operation(operand, ..);
        void Load(Register destination, ExternalReference source);
        void Store(ExternalReference destination, Register source);

        // Pushes the address of the external reference onto the stack.
        void PushAddress(ExternalReference source);

        // Operations on roots in the root-array.
        // Load a root value where the index (or part of it) is variable.
        // The variable_offset register is added to the fixed_offset value
        // to get the index into the root-array.
        void PushRoot(RootIndex index);

        // Compare the object in a register to a value and jump if they are equal.
        void JumpIfRoot(Register with, RootIndex index, Label* if_equal,
            Label::Distance if_equal_distance = Label::kFar)
        {
            CompareRoot(with, index);
            j(equal, if_equal, if_equal_distance);
        }
        void JumpIfRoot(Operand with, RootIndex index, Label* if_equal,
            Label::Distance if_equal_distance = Label::kFar)
        {
            CompareRoot(with, index);
            j(equal, if_equal, if_equal_distance);
        }

        // Compare the object in a register to a value and jump if they are not equal.
        void JumpIfNotRoot(Register with, RootIndex index, Label* if_not_equal,
            Label::Distance if_not_equal_distance = Label::kFar)
        {
            CompareRoot(with, index);
            j(not_equal, if_not_equal, if_not_equal_distance);
        }
        void JumpIfNotRoot(Operand with, RootIndex index, Label* if_not_equal,
            Label::Distance if_not_equal_distance = Label::kFar)
        {
            CompareRoot(with, index);
            j(not_equal, if_not_equal, if_not_equal_distance);
        }

        // ---------------------------------------------------------------------------
        // GC Support

        // Notify the garbage collector that we wrote a pointer into an object.
        // |object| is the object being stored into, |value| is the object being
        // stored.  value and scratch registers are clobbered by the operation.
        // The offset is the offset from the start of the object, not the offset from
        // the tagged HeapObject pointer.  For use with FieldOperand(reg, off).
        void RecordWriteField(
            Register object, int offset, Register value, Register scratch,
            SaveFPRegsMode save_fp,
            RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
            SmiCheck smi_check = INLINE_SMI_CHECK);

        // For page containing |object| mark region covering |address|
        // dirty. |object| is the object being stored into, |value| is the
        // object being stored. The address and value registers are clobbered by the
        // operation.  RecordWrite filters out smis so it does not update
        // the write barrier if the value is a smi.
        void RecordWrite(
            Register object, Register address, Register value, SaveFPRegsMode save_fp,
            RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
            SmiCheck smi_check = INLINE_SMI_CHECK);

        // Frame restart support.
        void MaybeDropFrames();

        // Enter specific kind of exit frame; either in normal or
        // debug mode. Expects the number of arguments in register rax and
        // sets up the number of arguments in register rdi and the pointer
        // to the first argument in register rsi.
        //
        // Allocates arg_stack_space * kSystemPointerSize memory (not GCed) on the
        // stack accessible via StackSpaceOperand.
        void EnterExitFrame(int arg_stack_space = 0, bool save_doubles = false,
            StackFrame::Type frame_type = StackFrame::EXIT);

        // Enter specific kind of exit frame. Allocates
        // (arg_stack_space * kSystemPointerSize) memory (not GCed) on the stack
        // accessible via StackSpaceOperand.
        void EnterApiExitFrame(int arg_stack_space);

        // Leave the current exit frame. Expects/provides the return value in
        // register rax:rdx (untouched) and the pointer to the first
        // argument in register rsi (if pop_arguments == true).
        void LeaveExitFrame(bool save_doubles = false, bool pop_arguments = true);

        // Leave the current exit frame. Expects/provides the return value in
        // register rax (untouched).
        void LeaveApiExitFrame();

        // Push and pop the registers that can hold pointers.
        void PushSafepointRegisters() { Pushad(); }
        void PopSafepointRegisters() { Popad(); }

        // ---------------------------------------------------------------------------
        // JavaScript invokes

        // Invoke the JavaScript function code by either calling or jumping.
        void InvokeFunctionCode(Register function, Register new_target,
            const ParameterCount& expected,
            const ParameterCount& actual, InvokeFlag flag);

        // On function call, call into the debugger if necessary.
        void CheckDebugHook(Register fun, Register new_target,
            const ParameterCount& expected,
            const ParameterCount& actual);

        // Invoke the JavaScript function in the given register. Changes the
        // current context to the context in the function before invoking.
        void InvokeFunction(Register function, Register new_target,
            const ParameterCount& actual, InvokeFlag flag);

        void InvokeFunction(Register function, Register new_target,
            const ParameterCount& expected,
            const ParameterCount& actual, InvokeFlag flag);

        // ---------------------------------------------------------------------------
        // Conversions between tagged smi values and non-tagged integer values.

        // Tag an word-size value. The result must be known to be a valid smi value.
        void SmiTag(Register dst, Register src);

        // Simple comparison of smis.  Both sides must be known smis to use these,
        // otherwise use Cmp.
        void SmiCompare(Register smi1, Register smi2);
        void SmiCompare(Register dst, Smi src);
        void SmiCompare(Register dst, Operand src);
        void SmiCompare(Operand dst, Register src);
        void SmiCompare(Operand dst, Smi src);

        // Functions performing a check on a known or potential smi. Returns
        // a condition that is satisfied if the check is successful.

        // Test-and-jump functions. Typically combines a check function
        // above with a conditional jump.

        // Jump to label if the value is not a tagged smi.
        void JumpIfNotSmi(Register src,
            Label* on_not_smi,
            Label::Distance near_jump = Label::kFar);

        // Jump to label if the value is not a tagged smi.
        void JumpIfNotSmi(Operand src, Label* on_not_smi,
            Label::Distance near_jump = Label::kFar);

        // Operations on tagged smi values.

        // Smis represent a subset of integers. The subset is always equivalent to
        // a two's complement interpretation of a fixed number of bits.

        // Add an integer constant to a tagged smi, giving a tagged smi as result.
        // No overflow testing on the result is done.
        void SmiAddConstant(Operand dst, Smi constant);

        // Specialized operations

        // Converts, if necessary, a smi to a combination of number and
        // multiplier to be used as a scaled index.
        // The src register contains a *positive* smi value. The shift is the
        // power of two to multiply the index value by (e.g. to index by
        // smi-value * kSystemPointerSize, pass the smi and kSystemPointerSizeLog2).
        // The returned index register may be either src or dst, depending
        // on what is most efficient. If src and dst are different registers,
        // src is always unchanged.
        SmiIndex SmiToIndex(Register dst, Register src, int shift);

        // ---------------------------------------------------------------------------
        // Macro instructions.

        void Cmp(Register dst, Handle<Object> source);
        void Cmp(Operand dst, Handle<Object> source);
        void Cmp(Register dst, Smi src);
        void Cmp(Operand dst, Smi src);

        // Checks if value is in range [lower_limit, higher_limit] using a single
        // comparison.
        void JumpIfIsInRange(Register value, unsigned lower_limit,
            unsigned higher_limit, Label* on_in_range,
            Label::Distance near_jump = Label::kFar);

        // Emit code to discard a non-negative number of pointer-sized elements
        // from the stack, clobbering only the rsp register.
        void Drop(int stack_elements);
        // Emit code to discard a positive number of pointer-sized elements
        // from the stack under the return address which remains on the top,
        // clobbering the rsp register.
        void DropUnderReturnAddress(int stack_elements,
            Register scratch = kScratchRegister);

        void PushQuad(Operand src);
        void PushImm32(int32_t imm32);
        void Pop(Register dst);
        void Pop(Operand dst);
        void PopQuad(Operand dst);

        // ---------------------------------------------------------------------------
        // SIMD macros.
        void Absps(XMMRegister dst);
        void Negps(XMMRegister dst);
        void Abspd(XMMRegister dst);
        void Negpd(XMMRegister dst);
        // Generates a trampoline to jump to the off-heap instruction stream.
        void JumpToInstructionStream(Address entry);

        // Non-x64 instructions.
        // Push/pop all general purpose registers.
        // Does not push rsp/rbp nor any of the assembler's special purpose registers
        // (kScratchRegister, kRootRegister).
        void Pushad();
        void Popad();

        // Compare object type for heap object.
        // Always use unsigned comparisons: above and below, not less and greater.
        // Incoming register is heap_object and outgoing register is map.
        // They may be the same register, and may be kScratchRegister.
        void CmpObjectType(Register heap_object, InstanceType type, Register map);

        // Compare instance type for map.
        // Always use unsigned comparisons: above and below, not less and greater.
        void CmpInstanceType(Register map, InstanceType type);

        void DoubleToI(Register result_reg, XMMRegister input_reg,
            XMMRegister scratch, Label* lost_precision, Label* is_nan,
            Label::Distance dst = Label::kFar);

        template <typename Field>
        void DecodeField(Register reg)
        {
            static const int shift = Field::kShift;
            static const int mask = Field::kMask >> Field::kShift;
            if (shift != 0) {
                shrq(reg, Immediate(shift));
            }
            andq(reg, Immediate(mask));
        }

        // Abort execution if argument is a smi, enabled via --debug-code.
        void AssertNotSmi(Register object);

        // Abort execution if argument is not a smi, enabled via --debug-code.
        void AssertSmi(Register object);
        void AssertSmi(Operand object);

        // Abort execution if argument is not a Constructor, enabled via --debug-code.
        void AssertConstructor(Register object);

        // Abort execution if argument is not a JSFunction, enabled via --debug-code.
        void AssertFunction(Register object);

        // Abort execution if argument is not a JSBoundFunction,
        // enabled via --debug-code.
        void AssertBoundFunction(Register object);

        // Abort execution if argument is not a JSGeneratorObject (or subclass),
        // enabled via --debug-code.
        void AssertGeneratorObject(Register object);

        // Abort execution if argument is not undefined or an AllocationSite, enabled
        // via --debug-code.
        void AssertUndefinedOrAllocationSite(Register object);

        // ---------------------------------------------------------------------------
        // Exception handling

        // Push a new stack handler and link it into stack handler chain.
        void PushStackHandler();

        // Unlink the stack handler on top of the stack from the stack handler chain.
        void PopStackHandler();

        // ---------------------------------------------------------------------------
        // Support functions.

        // Load the global proxy from the current context.
        void LoadGlobalProxy(Register dst)
        {
            LoadNativeContextSlot(Context::GLOBAL_PROXY_INDEX, dst);
        }

        // Load the native context slot with the current index.
        void LoadNativeContextSlot(int index, Register dst);

        // ---------------------------------------------------------------------------
        // Runtime calls

        // Call a runtime routine.
        void CallRuntime(const Runtime::Function* f,
            int num_arguments,
            SaveFPRegsMode save_doubles = kDontSaveFPRegs);

        // Convenience function: Same as above, but takes the fid instead.
        void CallRuntime(Runtime::FunctionId fid,
            SaveFPRegsMode save_doubles = kDontSaveFPRegs)
        {
            const Runtime::Function* function = Runtime::FunctionForId(fid);
            CallRuntime(function, function->nargs, save_doubles);
        }

        // Convenience function: Same as above, but takes the fid instead.
        void CallRuntime(Runtime::FunctionId fid, int num_arguments,
            SaveFPRegsMode save_doubles = kDontSaveFPRegs)
        {
            CallRuntime(Runtime::FunctionForId(fid), num_arguments, save_doubles);
        }

        // Convenience function: tail call a runtime routine (jump)
        void TailCallRuntime(Runtime::FunctionId fid);

        // Jump to a runtime routines
        void JumpToExternalReference(const ExternalReference& ext,
            bool builtin_exit_frame = false);

        // ---------------------------------------------------------------------------
        // StatsCounter support
        void IncrementCounter(StatsCounter* counter, int value);
        void DecrementCounter(StatsCounter* counter, int value);

        // ---------------------------------------------------------------------------
        // In-place weak references.
        void LoadWeakValue(Register in_out, Label* target_if_cleared);

        // ---------------------------------------------------------------------------
        // Debugging

        static int SafepointRegisterStackIndex(Register reg)
        {
            return SafepointRegisterStackIndex(reg.code());
        }

    private:
        // Order general registers are pushed by Pushad.
        // rax, rcx, rdx, rbx, rsi, rdi, r8, r9, r11, r12, r14, r15.
        static const int kSafepointPushRegisterIndices[Register::kNumRegisters];
        static const int kNumSafepointSavedRegisters = 12;

        // Helper functions for generating invokes.
        void InvokePrologue(const ParameterCount& expected,
            const ParameterCount& actual, Label* done,
            bool* definitely_mismatches, InvokeFlag flag,
            Label::Distance near_jump);

        void EnterExitFramePrologue(bool save_rax, StackFrame::Type frame_type);

        // Allocates arg_stack_space * kSystemPointerSize memory (not GCed) on the
        // stack accessible via StackSpaceOperand.
        void EnterExitFrameEpilogue(int arg_stack_space, bool save_doubles);

        void LeaveExitFrameEpilogue();

        // Compute memory operands for safepoint stack slots.
        static int SafepointRegisterStackIndex(int reg_code)
        {
            return kNumSafepointRegisters - kSafepointPushRegisterIndices[reg_code] - 1;
        }

        // Needs access to SafepointRegisterStackIndex for compiled frame
        // traversal.
        friend class StandardFrame;

        DISALLOW_IMPLICIT_CONSTRUCTORS(MacroAssembler);
    };

    // -----------------------------------------------------------------------------
    // Static helper functions.

    // Generate an Operand for loading a field from an object.
    inline Operand FieldOperand(Register object, int offset)
    {
        return Operand(object, offset - kHeapObjectTag);
    }

    // Generate an Operand for loading an indexed field from an object.
    inline Operand FieldOperand(Register object,
        Register index,
        ScaleFactor scale,
        int offset)
    {
        return Operand(object, index, scale, offset - kHeapObjectTag);
    }

    inline Operand ContextOperand(Register context, int index)
    {
        return Operand(context, Context::SlotOffset(index));
    }

    inline Operand ContextOperand(Register context, Register index)
    {
        return Operand(context, index, times_system_pointer_size,
            Context::SlotOffset(0));
    }

    inline Operand NativeContextOperand()
    {
        return ContextOperand(rsi, Context::NATIVE_CONTEXT_INDEX);
    }

    // Provides access to exit frame stack space (not GCed).
    inline Operand StackSpaceOperand(int index)
    {
#ifdef _WIN64
        const int kShaddowSpace = 4;
        return Operand(rsp, (index + kShaddowSpace) * kSystemPointerSize);
#else
        return Operand(rsp, index * kSystemPointerSize);
#endif
    }

    inline Operand StackOperandForReturnAddress(int32_t disp)
    {
        return Operand(rsp, disp);
    }

#define ACCESS_MASM(masm) masm->

} // namespace internal
} // namespace v8

#endif // V8_X64_MACRO_ASSEMBLER_X64_H_
